Another common eye disorder is diabetic retinopathy, when the blood vessels of the retina overgrow or leak. This can damage the retina, affecting vision, and eventually lead to blindness. All the things that help prevent type 2 diabetes, such as exercise, also help prevent diabetic retinopathy.

People can also have the equivalent of a stroke within the eye if a clot blocks one of the blood vessels that feed the retina. Such “retinal vein occlusions” can trigger transient or even permanent loss of vision.

The best way to avoid one is to do all the things that prevent a stroke in the brain, says Anne Sumers, a spokesperson for the American Academy of Ophthalmology. Stay active, watch your blood pressure and cholesterol levels, and above all, don’t smoke.